The protein expression core is designed to continue to provide highly purified recombinant proteins to each of the component projects. The core will provide advice about preparing cDNA expression constructs. Prokaryotic expression will be achieved primarily by use of vectors such as PET-15 or as fusion proteins with glutathione S-transferase or maltose-binding protein using vectors such as pGEX or pMAL. In selected cases, expression in insect cells will be employed to produce recombinant Fab fragments or when critical post-translational modifications are required for activity. The core will perform microbiological manipulations and fermentations. Proteins will be purified by affinity chromatography and fast protein and high performance liquid chromatography and chemically characterized by mass spectroscopy. The core will also prepare specialized novel model protein mimics of integrin cytoplasmic domains for analysis of interactions at the cytoplasmic face of these receptors